The present application relates to a reflector for improving luminance of a display device using a self-luminous light emitting element such as an organic EL (Electroluminescence) element, a display device having the same, and a method of manufacturing the same.
A self-luminous light emitting element such as an organic light emitting element has a first electrode, layers including a light emitting layer, and a second electrode in order on a substrate. When DC voltage is applied across the first and second electrodes, hole-electron recombination occurs in the light emitting layer, and light is generated. In some cases, the generated light is extracted from the first electrode side and the substrate. There is also a case that the generated light is extracted from the second electrode side, that is, the side opposite to circuits including a TFT (Thin Film Transistor) and wirings in order to increase the aperture ratio. In the case of extracting light from the second electrode side, generally, a metal electrode having high reflectance is used as the first electrode.
An example of a display device using a self-luminous light emitting element is a display device using an organic light emitting element as described in, for example, Japanese Unexamined Patent Application Publication No. 2005-227519. A display device of related art is provided with a light shield film as a so-called black matrix as a measure to increase contrast. The light shield film is provided to absorb outside light, decrease luminance of black level on the screen, and increase visibility, and is formed together with a color filter over a sealing substrate. In the case of a display device using an organic light emitting element, the color filter is used to regulate light emission wavelength and realize excellent color reproducibility.
In a display device using an organic light emitting element, it is also proposed to dispose a reflector near the organic light emitting element in order to increase display luminance to improve the efficiency of extracting light from the organic light emitting element as described in, for example, Japanese Unexamined Patent Application Publication No. 2001-85738.
However, the technique in related art relates to only the reflector. Examination on the structure including the function of a black matrix and a method of manufacturing the reflector has not been made, and there is room for improvement.
Further, in reality, the light shield film transmits light at the order of a few percents. Consequently, so-called retro-reflection such that outside light passed through the light shield film is reflected by a reflector film formed on the reflector and is returned to the observer side occurs. It causes a stray ray which induces contrast reduction.